I decided to run the OEM D7 Carter YF carb on my 250 headed '66 motor. I am running this carb until my 3X1 is all set up and correct. Before I begin just some background info, I installed an E-brock A/F meter in the header so I can tune the carb(s). What a wonderful tool, I highly recommened it to anyone after a rebuild or any type of non-OEM carb work.
Anyway....I rebuilt the D7carb, placed it on the head with the fired her up. It idled REAL lean.. I mean off the scale lean (higher than 15:1). I have triple checked the gaskets and there are no vac leaks. The idle mixture screw is sealed so there is no way to adjust the amount of A/F at idle. In checking things out I looked down the throat of the carb at idle and fuel was spilling out from the accel pump nozzle, but it was still idling lean. When I test drove it there was a stumble off of idle and had real bad low rpm reformance. I think the whole idle circuit is bascially not functioning. The A/F meter would show about 12:1 when I punched the gas (that tells me the accell pump system works
) and then settle out to just under 14:1 under continuous acceleration (that tells me the power circuit is working )
So after a few test drives and to just to see what was going on, I blocked the air bleed hole into the idle well with my finger. That raised the A/F mixture to the 13:1 to 12:1 range. So I put JB weld over it (better to have too rich than too lean I think
) and now at idle there is fuel spewing from the main venturi. 
So I gues my question(s) is/are: can I drill out the metal plug over the idle adjustment screw and then use a screwdriver to adjust the mixture? is the needle threaded so it can be adjusted or is it just a needle in a seat? is there any other way to make the idle circuit funtional?
tanx
Anyway....I rebuilt the D7carb, placed it on the head with the fired her up. It idled REAL lean.. I mean off the scale lean (higher than 15:1). I have triple checked the gaskets and there are no vac leaks. The idle mixture screw is sealed so there is no way to adjust the amount of A/F at idle. In checking things out I looked down the throat of the carb at idle and fuel was spilling out from the accel pump nozzle, but it was still idling lean. When I test drove it there was a stumble off of idle and had real bad low rpm reformance. I think the whole idle circuit is bascially not functioning. The A/F meter would show about 12:1 when I punched the gas (that tells me the accell pump system works
) and then settle out to just under 14:1 under continuous acceleration (that tells me the power circuit is working )So after a few test drives and to just to see what was going on, I blocked the air bleed hole into the idle well with my finger. That raised the A/F mixture to the 13:1 to 12:1 range. So I put JB weld over it (better to have too rich than too lean I think
) and now at idle there is fuel spewing from the main venturi. So I gues my question(s) is/are: can I drill out the metal plug over the idle adjustment screw and then use a screwdriver to adjust the mixture? is the needle threaded so it can be adjusted or is it just a needle in a seat? is there any other way to make the idle circuit funtional?
tanx
